Affiner votre recherche
Résultats 1-9 de 9
Effects of environmental stress on forest crown condition in Europe. Part IV: statistical analysis of relationships
2000
Klap, J.M. | Voshaar, J.H.O. | Vries, W. de | Erisman, J.W.
Effects of environmental stress on forest crown condition in Europe. Part I: hypotheses and approach to the study
2000
Vries, W. de | Klap, J.M. | Erisman, J.W.
Effects of environmental stress on forest crown condition in Europe. Part III: estimation of critical deposition and concentration levels and their exceedances
2000
Vries, W. de | Reinds, G.J. | Klap, J.M. | Leeuwen, E.P. van | Erisman, J.W.
[What is the use of groundwater chemistry surveillance?]
2000
Thorling, L. (Aarhus Amt (Denmark))
[Technology project: Phytoremediation of oil products at a disused filling station]
2000
Larsen, L.C. (Hedeselskabet, Viborg (Denmark)) | Trapp, S.
[Potentially pesticide contaminated sites: results from investigations in Aarhus, Ribe and Funen Counties]
2000
Christensen, L.
[Technology project: Natural degradation of PAHs in soil and groundwater]
2000
Knudsen, S. | Broholm, M. | Andersen, J.N. | Arvin, E.
Monitoring in the inner Oslofjord. Micro-pollutants in fish and common mussels 1997-1998
2000
Knutzen, J. | Brevik, E.M. | Foelsvik, N.A.H. (NIVA - Norsk Inst. for Vannforskning, Oslo (Norway)) | Schlabach, M.
Forest condition in Estonia in 1988-99, defoliation and forest damages on Level I sample points
2000
Karoles, K. | Ounap, H. | Pilt, E. | Terasmaa, T. | Kivits, H. (Estonian Centre of Forest Protection and Silviculture, Tartu (Estonia))
The highest defoliation in Estonia has continually been assessed in Scots pine though a permanent improvement of crown conditions of the trees has been observed since 1992. In 1996-99 there was a slight increase in the defoliation of Norway spruce and the steady decrease in defoliation, observed in 1989-95 stopped. The decrease in the defoliation of the Norway spruce is more noticeable in north-western and northern Estonia. Only 9.4 per cent of the Norway spruces and 8.9 per cent of the Scots pines were defoliated more than 25 per cent in 1999. The age of trees seems to have a great impact on both defoliation and discoloration of Norway spruce. Defoliation of older Norway spruces is higher than that of younger ones. Only 37 per cent of the older trees were defoliated less than 11.5 per cent and the proportion of such trees has decreased over the last four years. From Norway spruces younger than 60 years as many as 86 per cent of the trees were defoliated less than 11 per cent. In 27 sample points the Norway spruces had secondary shoots, in 16 points the proportion of the trees with secondary shoots was 10 per cent in 1999. In total the health state of the deciduous trees was markedly better than that of the conifers. For example, the share of healthy birches was 96 per cent in 1999
Afficher plus [+] Moins [-]